I want to fade a window in/out in my application. Fading in
occurs on Window.Loaded and I wanted to fade out on close (Window.Closed or
Window.Closing). Fading in works perfectly but a RoutedEvent is not allowed on
Window.Closing. What RoutedEvent should I be using for Close?

Closing is not a routed event, so you can't use it in an
EventTrigger. Perhaps you could start the storyboard in the handler of the
ClosingEvent in the code-behind and cancel the event... something like that :